Spin detent system



July 4, 1967 w. L. RHOADS SPIN DETENT SYSTEM Filed April 27, 1965 2 $heets$heet 1 William L. Rhoads I N VENTOR.

BYN

ATT RNEY.

AGENT.

July 4, 1967 w. L. RHOADS SPIN DETENT SYSTEM 2 Sheets-Sheet 2 Filed April 27, 1965 FIG. 5

FIG. 6

William L. Rhoads BY INVENTORY ATTORNEY.

AGENT.

United States Patent 3,329,090 SPIN DETENT SYSTEM William L. Rhoads, Laurel, Md., assignor to the United States of America as represented by the Secretary of the Navy Filed Apr. 27, 1965, Ser. No. 451,365 14 Claims. (Cl. 102-70) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to spin stabilized projectiles. More particularly, it relates to a centrifugally operated safety device or detent capable of initiating a fuzing function in such a projectile and positively preventing accidental detonation of the projectile which might be produced by shocks occurring during handling thereof.

In electric fuzes having deferred action batteries to supply them with electrical energy, the electrolyte for the battery is usually contained in :a frangible ampule mounted above a rupturing pin so as to be broken by the setback force when the projectile is fired. It is found however, that when electric fuzes are used in rockets or mortar shells, the initial force of setback is not always suflicient to break the ampule. To insure the release of the electrolyte into contact with the battery plates, a percussion type detonator is conventionally used, which is fired when the rocket or projectile attains a predetermined angular velocity to rupture the ampule if it should fail to break upon setback. Before the projectile is fired, mechanical detents holds the detonator, which is movable and spring actuated in a cocked position. The detents are held in place by the restraining action of springs until the projectile attains sufficient angular velocity to cause them to move outwardly under the influence of centrifugal force to thus release the detonator to move against its firmg pm.

A centrifugally operated detent system which has found extensive use in Navy projectiles is described in US Patent 2,900,908 issued to Burrell on Aug. 25, 1959. This device employs an interlocking set of centrifugal detents which are released after a predetermined sustained spin rate has been achieved to explode a detonator to .project a rupturing pin against the electrolyte ampule. A more complete description of the detonator release mechanism itself will be found in the detailed description to follow.

The existing detent system has several disadvantages. It has a large number of parts, requires many manufacturing and assembling operations, needs a relatively large amount of space, and is feasible for only relatively low spin values because of the large inertia forces resulting from the relatively large masses of the detent elements.

It is an object of the present invention to overcome the aforementioned disadvantages by providing a detent system for a spin actuated deferred action battery which is simpler than the prior system, has fewer parts, is easier to manufacture, and is more reliable and uniform in operation.

The objects of the invention are achieved by substituting for the prior inertia element detent system a flexible beam which is mounted in such a manner that it will deflect outwardly under the influence of the centrifugal force associated with the projectile spin to release the ampule breaking mechanism. The beam may be cantilevered or otherwise mounted as will become apparent 3,329,090 Patented July 4, 1967 from the following detailed description. In addition, auxiliary detent means may be provided for added safety.

Other objects, advantages and new features of the present invention will become apparent from a reading of the following detailed description when taken into conjunction with the accompanying drawings wherein:

FIG. 1 is a partial diagrammatic showing of a detonator release mechanism;

FIG. 2 is a plan view of one embodiment of the detent system of the present invention;

FIG. 3 is a plan view of a second embodiment of the invention;

FIG. 4 is a plan view of still another embodiment of the invention; and

FIGS. 5, '6 and 7 are plan views of three auxiliary detent mechanisms which may be employed with a cantilevered beam of the type disclosed in FIG. 2.

Referring now to FIG. 1, the ampule breaking mechanism consists essentially of a detonating element 10 which is biased to the left as seen in FIG. 1 by means of a spring 11. It will be understood, of course, that guide means are provided to restain the detonating element to move in the direction of its longitudinal axis, and that means are provided to confine and compress spring 11. A firing pin 12, which is fixed in the housing of the device, serves to explode the detonator 10 when it is projected against the firing pin by spring 11. It will be understood that the expanding gases from detonator 10 then act to break the electrolyte ampule in the battery.

' Mounted in the housing of the device in a manner to be rotatable about its longitudinal axis is a triggering means or half-shaft 13. Half-shaft 13 as shown in FIG. 1,

is provided with a diametrically extending flat surface 14, which is in an abutting relation to the end face of the detonator 10 when the half-shaft is in its unreleased position. The half-shaft 13 is held in the position shown in FIG. 1 by the cooperative action of the detent system of the invention by means of a restraining pin 16 rigidly connected to the half-shaft 13 and extending radially therefrom. It should be apparent from FIG. 1 that if the halfsh-aft were released to rotate counterclockwise around its longitudinal axis, under the action of spring 11, that the surface 14 would be thus moved out of the way of detonator 10 after the half-shaft has rotated 7 FIG. 2 illustrates a first embodiment of the detent according to the invention. In this figure, as in all of the figures to follow, the detent of the invention is mounted on a plate 17 which lies in a radial plane in the projectile. It will be understood that plate 17 has an opening through which the upper end of the half-shaft 13 extends.

The detent means in the embodiment of FIG. 2 is in the 7 form of an elongated spring member 18 of rectangular cross-section. Spring 18 is fixedly secured in an upstanding post 19 mounted on the plate 17 so that the axis of flexibility thereof is perpendicular to the plane of the figure. In this manner, the spring 18 may flex in a plane parallel to the plane of the figure.

As suggested in FIG. 1, the spring 18 is provided with an aperture 22. Pin 16 on half-shaft 13 passes through aperture 22 when the beam18 is in its unflexed condition so that half-shaft 13 is prevented from turning. In operation, when the projectile is fired or launched, and stabilizing spin is imparted to it, the spring 18 will deflect outwardly to free the pin 16 and allow the half-shaft to turn to the dotted line position 16' shown.

It will be apparent that the amount of deflection of beam 18 for a predetermined spin value can be varied by adjusting the sizes or the spring constant of the beam.

In the embodiment according to FIG. 3, the spring, which is there designated as 18a, is not mounted in cantilever fashion, but instead is supported at each end. The principal advantage of this construction over that of FIG. 2 is the elimination of the assembly operatlon required to rigidly secure the beam 18 in the post 19. In the FIG. 3 embodiment, the beam is simply wrapped around a supporting post 23 at one end and lies against a post 24 at the other. In a manner similar to the FIG. 2 embodiment, the FIG. 3 beam 18a has an aperture through which the pin 16 passes. In addition, an auxiliary weight element or inertia block 26 may be provided to increase the deflection of the beam 18a for a given spin rate.

The FIG. 3 embodiment operates like the embodiment of FIG. 2. When the beam deflects outwardly under centrifugal force, the aperture in the beam moves outward free of the end of pin 16 and the half-shaft is then freed to turn to the dotted line position shown.

FIG. 4 illustrates another embodiment of the invention which is similar to the FIG. 3 embodiment but illustrates a variation in the manner in which the beam cooperates with the half-shaft. In this embodiment, the half-shaft is provided with a bore 27 instead of the restraining pin 16. A beam 18!) is employed which is mounted on the plate 171; in the same way as the beam 180 is mounted in FIG. 3. Rigidly attached to beam 18b is a pin 28, which in the unflexed condition of the beam enters the aperture 27 in the half-shaft and thereby prevents rotation of the halfshaft. A weight or inertia element 29 may also be provided to vary the deflection for a given spin. In the operation of this embodiment, the outward deflection of the beam 18b withdraws the pin 28 from the aperture 27 to free the half-shaft.

Additional safety may be required if the projectile in which the device of the invention is incorporated is to be subjected to sudden relatively severe shocks during handling or storage. FIGS. thru 7 illustrate several ways in which this additional safety can be accomplished. In each of these embodiments, the end of the beam 18c, 18d or 184: is confined in a slot in an inertia element 31c, 31d and 31:: which is guided in plate 17 by means of a slot 36. It will be apparent that an impact or acceleration of the body of the projectile in the direction of the arrow A in FIG. 5 will result in no deflection of the safety element 31c, but might, in the absence of the safety element 310, result in enough deflection of the beam 180 in the opposite direction to free the half-shaft. On the other hand, accelerations in the direction shown by the arrow B in FIG. 5 which might cause the safety element 310 to be withdrawn from its cooperation with beam 180 are not in the proper direction to have any effect on beam 18c. Thus complete handling safety is provided, in that the only way that the detent systems of FIGS. 5 thru 7 can be actuated is for the projectile to be subjected to a sufl'icient amount of spin first to centrifugally release the restraining detents 31c, 31d or 31e and then to cause the outward deflection of the beams 18c, 18d or 18e to release the half-shaft. Spring control of the detents 31c, 31d or 31c may be accomplished in any desired manner as by coil spring 32 as in FIG. 5, an Omega spring 33 as in FIG. 6, or by leaf spring 34 as illustrated in FIG. 7.

It will be apparent to those skilled in the art that the details of the invention are subject to wide modification. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as herein specifically described.

What is claimed is:

1. In a fuzing system for a spinning projectile,

a single, elongate, flexible beam fixedly mounted in said projectile,

the axis of flexibility of said beam being parallel to the spin axis of said projectile so that said beam can deflect in a radial plane of said projectile,

triggering means mounted in said projectile, said triggering means being rotatable about an axis parallel to said spin axis and being spring biased to move from a first, unfuzed position to a second, fuzed position,

said triggering means having restraining means thereon which cooperate with means on said beam when said projectile is at rest to prevent motion of said triggering means to its second position.

2. A fuzing means as recited in claim 1, wherein said flexible beam is mounted in cantilever fashion with one of its ends secured and its other end free.

3. A fuzing means as recited in claim 2, wherein said restraining means comprises a transversely extending pin on said triggering means, said beam having an aperture therethrough, through which the pin extends when said projectile is at rest.

4. A fuzing means as recited in claim 1, wherein said beam is fixedly mounted at one of its ends in said projectile and is slideably mounted but radially restrained at its other end.

5. A fuzing means as recited in claim 4, wherein said restraining means comprises a transversely extending pin on said triggering means, said ibeam having an aperture therethrough, through which'the pin extends when said projectile is at rest.

6. A fuzing means as recited in claim 4, wherein said restraining means comprises a radial bore in said triggering means, said beam having a pin fixed thereon which extends into said bore when said projectile is at rest.

7. A fuzing means as recited in claim 4, wherein an auxiliary inertia block is secured to said beam at the mid-portion thereof.

8. A fuzing means as recited in claim 6, wherein an auxiliary inertia block is secured to said means at the mid-portion thereof.

9. In a fuzing system for a spinning projectile having a deferred action battery and mean-s for activating said battery, a spin responsive detent for preventing operation of said activating means until a predetermined spin is achieved, said detent comprising a single, elongate, flexible beam fixedly mounted in cantilever fashion in said projectile with one of its ends secured and the other free, the axis of flexibility of said beam being parallel to the spin axis of said projectile so that said beam can deflect in a radial plane in said projectile, and

means on said beam in cooperative relation to said activating means when said projectile is at rest for positively preventing operation thereof.

10. A detent as recited in claim 9, said activating means having a triggering means rotatively mounted in said projectile from a first unfuzed position to a second position in which said battery is activated,

said triggering means having a transversely extending restraining pin thereon,

said beam having an aperture near the free end thereof, said restraining pin extending through said aperture in the rest condition of the projectile.

11. A detent as recited in claim 10, wherein auxiliary detent means are provided to prevent inadvertent activation of said battery due to transverse impacts on said projectile, said auxiliary detent means comprising an inertia element slideably mounted in said projectile and constrained to move in a direction colinear with the longitudinal axis of said beam, said inertia element having a slot in one end thereof, said slot receiving the free end of said beam in the rest condition of said projectile, and

spring means for opposing the inertia force of said inertia element, the mass of said inertia element and the spring constant of said spring being selected to establish release of said beam at a predetermined rate of spin of said projectile.

12. A detent as recited in claim 11 wherein said spring is a coil spring.

5 6 13. A detent as recited in claim 11 wherein said spring 2,458,474 11/1949 Jordan 102-70.2 X is an Omega spring. 2,516,323 7/1950 Jordan 102-79 14. A detent as recited in claim 11 wherein said spring 2,900,908 8/ 1959 Burrell 102-79 X is a leaf spring. 3,045,597 7/1962 Linn 102-79 References Cited 5 UNITED STATES PATENTS BENJAMIN A. BORCHELT, Prlmariy Examzner. 2 3 2 9 7 11 ,1944 Church et 1 1 G. H. GLANZMAN, Asszstant Examiner. 

1. IN A FUZING SYSTEM FOR A SPINNING PROJECTILE, A SINGLE, ELONGATE, FLEXIBLE BEAM FIXEDLY MOUNTED IN SAID PROJECTILE, THE AXIS OF FLEXIBILITY OF SAID BEAM BEING PARALLEL TO THE SPIN AXIS OF SAID PROJECTILE SO THAT SAID BEAM CAN DEFLECT IN A RADIAL PLANE OF SAID PROJECTILE, TRIGGERING MEANS MOUNTED IN SAID PROJECTILE, SAID TRIGGERING MEANS BEING ROTATABLE ABOUT AN AXIS PARALLEL TO SAID SPIN AXIS AND BEING SPRING BIASED TO MOVE FROM A FIRST, UNFUZED POSITION TO A SECOND, FUZED POSITION, 